We help IT Professionals succeed at work.

We've partnered with Certified Experts, Carl Webster and Richard Faulkner, to bring you two Citrix podcasts. Learn about 2020 trends and get answers to your biggest Citrix questions!Listen Now


VB.NET Compile Error - Namespace cannot be found

dave4dl asked
Medium Priority
Last Modified: 2010-08-05

This is probably a simple question because i am a newbie at this.  I have created a vb class in the visual studio 2002 environment.  I can compile and test the class just fine through the IDE but when i try to compile the code using vbc.exe it generates an error.

I run:

"F:\WINDOWS\Microsoft.NET\Framework\v1.0.3705\vbc" /nologo /t:library "F:\My Programs\Mp3 Cataloger\mp3Info.vb"

And then i get:

F:\My Programs\Mp3 Cataloger\mp3Info.vb(4) : error BC30466: Namespace or type 'RegularExpressions' for the Imports 'System.Text.RegularExpressions' cannot be found.

Imports System.Text.RegularExpressions

The weird thing is my other imports work just fine (listing of imports following):

Imports System.IO
Imports System
Imports Microsoft.VisualBasic
Imports System.Text.RegularExpressions

When i dont include the regular expressions (and i comment out the instances of regex i create in the code) it compiles just fine.

Can anyone tell me how to make this compile?
Watch Question

Do you have a path to your C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727 or v1.4.3 etc etc etc...or 1.03 etc etc



my user "path" environmental variable is:

F:\Program Files\Microsoft Visual Studio\Common\Tools\WinNT;F:\Program Files\Microsoft Visual Studio\Common\MSDev98\Bin;F:\Program Files\Microsoft Visual Studio\Common\Tools;F:\Program Files\Microsoft Visual Studio\VC98\bin;F:\WINDOWS\Microsoft.NET\Framework\v1.0.3705

system "path" variable =

%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;F:\Program Files\Microsoft SQL Server\80\Tools\BINN;F:\WINDOWS\Microsoft.NET\Framework\v1.0.3705
Try this

vbc class1.vb /reference:System.dll /target:library

RegularExpressions is part of the system.dll namespace and not the vb name space, I'm assuming because you are compiling with vbc the compiler adds the vb dll automatically and so you don't have to add it as a reference as well.

Not the solution you were looking for? Getting a personalized solution is easy.

Ask the Experts


Thanks for the post Wabbit,
I did try that reference and it didnt seem to help.

I found an interesting page at http://www.windowsdevcenter.com/pub/a/oreilly/windows/news/csharp_0101.html

that says i should reference System.Text.RegularExpressions.dll but i cannot find that file anywhere on my system.  I updated the .NET framework 1 and i still cannot find it.  How do i get this file?  Are regular expressions not available unless you buy the Visual Studio IDE?


Well tried referencing System.dll in my compile command and it worked.  I could have sworn i tried that earlier and it didnt work. Maybe I updated .NET framework . . .

Oh well, thanks for the help LordWabbit
Access more of Experts Exchange with a free account
Thanks for using Experts Exchange.

Create a free account to continue.

Limited access with a free account allows you to:

  • View three pieces of content (articles, solutions, posts, and videos)
  • Ask the experts questions (counted toward content limit)
  • Customize your dashboard and profile

*This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.


Please enter a first name

Please enter a last name

8+ characters (letters, numbers, and a symbol)

By clicking, you agree to the Terms of Use and Privacy Policy.